Numerous approaches to improving acoustic energy radiation have been undertaken in the prior art. Straight line loudspeaker arrays have been used, but require complex delay, frequency or amplitude shading to be effective over a limited range of frequency coverage. Another conventional loudspeaker array is the J-array design which requires separate frequency-amplitude equalization for straight and curved portions of the array due to the abrupt discontinuity in array shape.
A third approach to designing loudspeaker arrays has been to distribute the array along an arcuate line. As described in U.S. Pat. No. 6,112,847 and U.S. Pat. No. 6,394,223, the output ports of a series of compression drivers are coupled to the inlets of corresponding throat sections. The mouths of the throat sections are then acoustically coupled to a single array wave guide that is shaped as an arc in the vertical plane. While this approach is thought to improve energy distribution along the vertical plane, it still suffers from several drawbacks, including the need for slowly expanding throat sections, which increase distortion, and create internal reflections that alter the sound due to the expansion discontinuity where the mouths of the throats join the inlet aperture of the waveguide.
Thus, there is still an unsatisfied need for a curved line array loudspeaker design which overcomes one or more of the aforementioned drawbacks.